Lotus 'Safe & Sound' system makes hybrid, electric vehicles audible

Greetings. I received the following article, originally posted on CNet, from an email list. After reading this, it sounds like someone is starting to take notice and do something about the hybrid car issue. Please excuse any formatting errors and enjoy.

Lotus 'Safe & Sound' system makes hybrid, electric vehicles audible

"Due to the almost silent operation of hybrid and electric vehicles
running
on electric power at slow speeds, blind and partially sighted
pedestrians
may
be at risk while crossing roads or walking through parking lots since
they
cannot hear the vehicles as they approach.

Lotus Engineering, a name most commonly associated with lightweight
sports
cars, has announced that it has developed a system to synthesise
external
sound
on electric and hybrid vehicles to make them more audible to
pedestrians
and
cyclists. A simulation of a real engine sound is used on
Lotus' Safe &
Sound
Hybrid technology demonstrator vehicle, making it instantly
recognisable that the vehicle is in motion.

The demonstration vehicle is a
Toyota Prius
equipped to demonstrate the sound synthesis application. The
solution
Lotus
has devised is a re-application and development of its Sound
Synthesis technology, a suite of technologies originally
designed to reduce the amount of
cabin
noise in a conventional motor vehicle by using active sound
cancellation.

An artificial engine sound is played through a waterproof
loudspeaker in
the
car's nose, compensating for the lack of engine noise emitted by the
vehicle
when running on an electric motor. Because it's just a speaker, Lotus
can
make any sound they want, but they've stuck to using an
existing engine sound that makes the vehicle instantly
recognisable, with the pitch and
frequency
helping to identify its distance and speed. Front-facing
speakers mean
that
once the vehicle has passed, the sound is no longer heard.

In electric-only vehicles, the system is always on, but for
hybrids the system only operates when the vehicle is using
electric power. If the hybrid's engine starts operating -
either at higher speeds, higher throttle demands, or lower
battery levels - the control system automatically stops the
external
synthesis.
It is all completely automatic and, according to Lotus, the
driver hears almost none of the additional sound."